Automatic feed mechanism for punch presses



June 15, 1943. w. M. ANDERSON AUTOMATIC FEED MECHANISM FOR PUNCH PRESSES 2 Sheets-Sheet 1 Filed June 26, 1941 fnven/ior AZZprn/eys June 15, .1943. 'w. M. ANDERSON AUTOMATIC FEED MECHANISM FOR PUNCH PRESSES Filed June 26, 1941 2 Sheets-Sheet 2 Ratented June 15, 1943 AUTOMATIC FEED MECHANISM FOR PUNGH PRESSES William M. Anderson, Minneapolis, Minn., assignor to F. J. Kernel and himself, Minneapolis, Minn, a copartnership Application June 2-6, 1941, Serial No. 399,790

3 Claims. (o1.164- -ss) My present invention relates to and provides a simple and highly efficient automatic stock strip feeding mechanism for punch presses and, generally stated, consists of the novel devices,

combinations of devices, and arrangement of parts, hereinafter described and defined in the claims.

The objects of this invention, briefly stated, are simplicity of construction, accuracy and dependability in operation, and means for quick and accurate adjustments to the various kinds of step by step movement required to accurately feed the stock strip to the punch press.

In this improved device the stock strip is not pushed forward to the press but is drawn rearward or away from the press after an initial punching has been produced; and this is highly important especially when the stock strips are very thin sheet metal such as sheet brass or copper which would readily buckle under a forward pushing action. Moreover, this improved arrangement utilizes the holes formed in the stock strip as an element in determining the accurate feed movement.

, In this improved feed mechanism the partially punched stock strip is drawn to the press by the automatic action of a feed dog that is arranged to pull the strip forward from the press 'a greater distance than the desired step of forward movement; and the said feed dog, under return movement, moves the strip slightly backward against a stop dog which finally determines the punching position of the strip and then rides over an unpunched portion of the strip into engagement with a hole in the strip that is located forward of the last punched hole. All of these actions are completely automatic and are timed so that the stock strip will be left standing still while the press punch is given its punching and retracting movements.

A commercial form of the improved machine is illustrated in the accompanying drawings wherein like characters indicate like parts throughout the several views.

Referring to the drawings:

Fig. 1 is a side elevation showing the main punching elements of an ordinary punch press and showing my improved stock strip feeding mechanism associated therewith and arranged to be operated by the press;

Fig. 2 is a plan view of the strip feeding mechanism proper disconnected from the press;

Fig. 3 is a view in elevation looking at the mechanism of Fig. 2 in a direction from right toward the left and showing the punch-actuated lug or bracket of the press removed from the punch head and sectioned on the line 3-3 of Fig. 1;

Fig. 4 is a vertical section taken substantially on the line 4- of Fig. 2;

Fig. 5 is a horizontal section taken substantially on the line 55 of Fig. 4;

Fig. 6 is a transverse vertical section taken substantially on the line li6 of Fig. 4;

Fig. '7 is a detail view in section taken axially through the adjustable head or stud of the punch-actuated lug or bracket shown in Fig. 1 and in detail in Fig. 8, wherein the said parts are sectioned on the line 7-1; and

Fig. 8 is a detail in section taken on the line 88 of Fig. '7, some parts being broken away.

In Fig. 1 the numeral Ill indicates the bed, the numeral II the die plate, the numeral l2 the stripper plate, the numeral l3 the reciprocating punch head, the numeral M the punch pad, and the numeral E5 the punch. The said elements Ill, Ill and I2 will be provided with the customary punch or slug passages. In this application of the feed mechanism to the punch the reciprocating punch head I3 is provided with a rigidly secured laterally projecting feed lug or bracket it which, in its projecting end, has a-lo-ngitudinal slot ll. Adjustably mounted on the slotted end of the bracket I6 is an operating head in the form of a stud l8, see particularly Figs. 1, 7 and 8, the stem of which is extended through the slot I1 and the threaded end of which is equipped with a clamping nut IS. The projecting end of the stud I8 is preferably equipped with a roller 20.

The metallic stock strip a, as is common practice, is guided over the die plate I l and under the stripper plate l2, and from thence will be delivered to the feed mechanism, the preferred form of which is nOW to be described.

The stock strip a will be intermittently moved in a direction from the right toward the left in respect to Fig. 1. From the face of the die plate H, the punched stock strip will be delivered onto the upper face of a feed table, the upper surface of which is preferably in a true horizontal plane with the upper surface of the die plate II. This feed table may be formed in different ways but preferably, and as shown, is made up of three fiat elements, to wit: a rectangular lower plate 2|, an intermediate plate 22, and a facing plate or strip 23. The facing strip 23 is shown as rigidly but detachably secured to the intermediate plate 22 by screws 24; and the intermediate plate 22 is rigidly but dc,-

tachably secured to the base plate 2| by screws 25. The feed table made up of the said rigidly secured elements are, in turn, rigidly secured to the bed plate ID by suitable means, such as machine screws 26, and project from said base I with the upper surface of the facing strip 23, as already stated, on the level of the top of the die plate ||,'as shown in Fig. 1. For an important purpose presently to be described, the face plate 23, in its top, is provided with longitudinal grooves or channels 21.

Rigidly secured to the feed table, preferably by machine screws 28, are upright parallel laterally spaced side or frame plates 29 that are formed on their inner faces with grooves 30 to receive a longitudinally reciprocating feed plate or slide 3|. By means of screws 32, or otherwise, a U-shaped lug 33 is rigidly secured on top of the reciprocating plate or slide 3|. In the flanges of the lug 33 is a wrist pin 34 which is shown as roller-equipped.

Seated in the upper portions of the side frames 29 is a pivot pin or short shaft 35 on which is pivoted a segmental rocker 36 preferably of flat or plate-like form. At its lower edge this rocker segment 36 has circumferentially spaced lugs 31 that operate on the roller-equipped wrist pin 34 in a properly timed manner that will appear in the description of the operation. This rocker segment 36 has a slotted arm 38 in the slot of which the roller-equipped end of the head-forming stud l8 of the press-actuated lug or bracket i6 is adapted to work.

As best shown in Fig. 4, the feed dog is indicated by the character 39 and the back stop dog by the numeral 40. The feed dog 39, at its rear end, has a sleeve-like hub 4| which, by a pivot pin 42, is pivoted to lugs of an anchoring bracket 43 which, in turn, is rigidly but adjustably secured to the bottom of the feed plate 3| by means of machine screws 44. These screws .44 work through a clamping strip 45 and through :longitudinal slots 46 in the plate 3| and are screwed into the plate-like top of bracket 43. At its free end the feed dog 39 has a rearwardly .beveled feed lug 41 and an upwardly curved forwardly projected finger 4B. A leaf spring 49, shown as of U-shaped form, is anchored to the top of the bracket 43 with its transverse forward portion lightly pressing downward on feed 'dog 39. Here it will be noted that the feed lug 41 of dog 39 normally is in the groove 21 of facing plate 23. A leaf spring 50, at its rear end, is secured to the feed plate 3| with its free end frictionally engaging the top of the stock strip a, thereby keeping the latter pressed downward on the top of plate 23.

The back stop dog 40, which is preferably of substantially the same form as feed dog 39, is provided at its rear end with a sleeve-like hub which, by a pivot pin 52, is pivotally connected to the forwardly projecting prongs of an approximately U-shaped rectangular anchoring bracket 53 which, by means of machine screws 54, is rigidly but adjustably secured to the base of the side plates 29. These machine screws 54 work through slots 55 in the side plates and thereby serve to rigidly but adjustably secure said bracket 53 to the side frames with freedom for forward and rearward adjustments thereof and of the stop dog 40. Stop dog 40 is provided with a depending rearwardly beveled stop lug 56 and with an upwardly and forwardly extended finger 51.

A leaf spring 58 is attached to the base of the anchoring bracket 53 and exerts light downward pressure on the stop dog 40. The stop lug 56 normally works in the rear longitudinal channel 21. As simple and eificient means for engaging the edges of the stock strip and guiding the same for true longitudinal movement and against lateral shifting movements, I provide adjustable guides in the form of links 59, the rear ends of which, by means of screws 66 or the like, are pivoted to blocks 6| rigid on the outer sides of the fixed plate 22, as best shown in Figs. 1 and 5. The free edges of these links 59 serve as the guide for engagement with the edges of the stock strip. As a means for initially guiding the advance end of the stock strip under the stop dog and feed dog, I attach thin plates 62 thereto by rivets or otherwise. The rearwardly extended portions of these guide plates 62 are slightly upwardly extended as indicated by dotted lines in Fig. 4.

Operation The summary of the operation of the device described is as follows. As already indicated, the punched stock strip is not pushed but is drawn from the press under tension. My improved feed device determines the extent of the intermittent movements of the stock strip and properly positions the same under the punch, these operations, of course, being performed under the automatic control of the punch head.

The extent of oscillatory movement imparted to the rocker 36 may be varied by adjustments of the stud or head I8 in the slotted arm 38 of said rocker. The forward movement of slide 3|, and hence of feed dog 39, will be produced by engagement of rear lug 31 with wrist pin 34 of the feed plate or slide 3|; and the reverse or rearward movements of said parts 3| and of feed dog 39 will be produced by contact of the front lug 31 with said wrist pin. Moreover, both of the above movements will take place while the press is producing punching and retracting movements and while the rocker 36 is moving from one 01 erative position to the other and While there is no cgzitact between the said rocker and the wrist pin Forward and rearward adjustments of the feed dog 39 will determine the points at which the stock strip will be stopped in its forward movement; and forward and rearward adjustments of the stop dog 40 will determine the position that the stock strip will occupy after the strip has been stopped in position for punching. The lugs 41 and 56 of dogs 39 and 45, respectively, engage the strip in the holes or punctures made in the strip. The adjustment of movements of rocker 36 should be such that the stock strip will be given advance movements slightly greater than the desired space between holes or punctures in the stock strip. Under rearward movements of the feed plate or slide 3| feed dog 39 will be moved rearward until the beveled face of its lug engages the next adjacent uncut portion of the stock strip and then, with a frictional action thereon, will move the stock strip slightly rearward until it is intercepted by the lug 56 of the stop dog and this final action determines the punching position of the stock strip under the die l5.

However, the slightly continued rearward movement of feed dog will cause the lugs 41 thereof to ride over the stock strip into engagement with the hole next rearward and will then be in position to engage and feed the stock strip forward as before under the next forward movement of the slide 3| and feed dog.

It is important that the feed dog and stop dog be adjustable so that the former will determine the forward movement of the strip and the latter will stop rearward movement of the strip in the exact desired position and then become a base of reaction causing the feed dog to engage the next hole in the stock strip preparatory to the next feed movement.

By pivotal or lateral adjustments the links 59 can be set for stock strips varying in width. The end of spring 50 not only holds the stock strip down on the table but has a frictional contact with the strip that assists the lug 41 to impart the slight return or backward movement of the stock strip against the lug 56 of stop dog Obviously; this feed device will operate on the punched stockstrip regardless of whether the stock strip is of the character wherein the punched out slugs or the punched strip are the desired elements of the operations.

A commercial form of this improved device has been described; butit will be understood that the same is capable of various modifications and arrangement of parts all within the scopeiof the invention herein broadly claimed.

In this specification the following terms have been used synonymously, to wit: feed deck equals feed table; feed plate or slide; rocker or oscillating lever; and punch-actuated lug or bracket.

What I claim is:

1. In a device of the kind described, the combination with a reciprocating punch, and coopcrating die, and a feed table arranged to receive punched strips from between said punch and die, of a stop dog mounted on said feed table and operative on the punctures in said strip to posi tively limit the backward motion of said strip but permitting free forward movement thereof, a feed slide mounted to reciprocate over said feed table, longitudinally of the strip, a feed dog carried by said slide and operative on the punctures in said strip to positively feed the stock strip forward, means timed in respect to the movement of said punch and operative thereby, while said punch is raised from the die, to impart feeding movements to said slide and feed dog in excess of the spacing of the punctures of said stock strip and operative on return movement of said feed dog to move said stock strip backward as far as permitted by said stop dog.

2. The structure defined in claim 1 in which said feed dog is provided at its operative free end With 2. depending pivotal lug which by a frictional dragging action produces the backward feed action of the stock strip against said stop dog. 4

3. The structure defined in claim 1 in which the punch member is provided with a projecting arm in combination with a rocker pivotally supported above said table, said rocker having a slotted arm connected to the arm carried by said punch slide to impart the forward and rearward movements to said slide and the feed dog carried thereby.

WILLIAM M. ANDERSON. 

